34 NEW-YORK FAUNA — MOLLUSCA. 



Var. a. With a prominent acute carina, and destitute of protuberances (PI. 2, fig. 16). This 



forms the Carocolla helicoides of Lea, cited above. 

 Var. b. Also carinate, but with a smooth epidermis, and a single tooth on the outer lip. 



H. obstricta of Say. Western States. 

 Var. c. Carinate ; the oblique striae widely separated and distant. H. carolinensis of the 

 same author. 

 As far as I have had opportunities for the examination of this remarkable species, its 

 northernmost limits do not appear to extend beyond this State. It has been found at Niagara, 

 near Troy, and in the neighborhood of New York. According to Dr. Eights of Albany, this 

 species appears to affect more especially the Limestone region. In the latest European con- 

 chological works, this species figures under the name of denotata, which was applied to it 

 by Ferussac, without being aware of Say's previous description. I entirely concur with Mr. 

 Binney in the synonimes of this species, although I have had no opportunity of making a 

 personal examination of all the varieties. 



Helix dentifera. 



PLATE II. FIG. 17. A. B — (STATE COLLECTION.) 

 Helix dentifera. Binney, Jour. Nat. Hist. Vol. 1, p. 494, pi. 21. 



Description. Shell subglobose, somewhat flattened. Spire depressed. Whorls five, convex, 

 with numerous minute oblique striae. Suture distinct. Lip broadly and abruptly reflected, 

 occasionally with a slight process near its lower margin. Pillar-lip with an oblique prominent 

 tooth, nearly parallel with the upper margin of the aperture. Umbilicus closed by the broadly 

 reflected outer lip. 



Color. Epidermis yellowish horn, immaculate. Tooth white. Animal brownish above, 

 greyish on the sides. 



Diameter, 0'7. Height, 0-3. 



This species was first described by Mr. Binney from Vermont. It does not appear in the 

 most recent list of the shells of Massachusetts. It seems to be a rare species, but will in 

 all probability be detected in this and the adjoining eastern States. 



Helix diodonta. 



PLATE II. FIG. 18. A. B. —(STATE COLLECTION.) 



Helix diodonta. Say, Long's Exped. St. Peters, Vol. 2, p. 257, pi. 15, fig. 4. 

 H. id. Wheatley, Cat. of Shells of the U. S. No. 470. 



Description. Shell moderately large, somewhat depressed. Spire convex, very little ele- 

 vated. Whorls five, regularly and prominently wrinkled and grooved transversely. Aperture 

 moderate regular. Lip moderately reflected, with a slightly projecting tooth-like callus near 



